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changeset 4305:f68047884e83

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Protection from stale write events in epoll. Stale write event may happen if epoll_wait() reported both read and write events, and processing of the read event closed descriptor. Patch by Yichun Zhang (agentzh).
author Maxim Dounin <mdounin@mdounin.ru>
date Tue, 22 Nov 2011 17:02:21 +0000
parents ed922fb9d6c1
children 05f3174483de
files src/event/modules/ngx_epoll_module.c
diffstat 1 files changed, 12 insertions(+), 0 deletions(-) [+]
line wrap: on
line diff
--- a/src/event/modules/ngx_epoll_module.c
+++ b/src/event/modules/ngx_epoll_module.c
@@ -681,6 +681,18 @@ ngx_epoll_process_events(ngx_cycle_t *cy
 
         wev = c->write;
 
+        if (c->fd == -1 || wev->instance != instance) {
+
+            /*
+             * the stale event from a file descriptor
+             * that was just closed in this iteration
+             */
+
+            ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
+                           "epoll: stale event %p", c);
+            continue;
+        }
+
         if ((revents & EPOLLOUT) && wev->active) {
 
             if (flags & NGX_POST_THREAD_EVENTS) {